RE: [Histonet] formalin precipitate/Iron artifact

From:"Marshall Terry Dr, Consultant Histopathologist"

Am I in a parallel universe?

Iron from a few seconds in a stainless steel needle?
Is this some soluble iron salt? If so how does it survive watery fixation and processing?
Is it insoluble iron? If so what is it doing on the surface of stainless steel?
Saundra Johnson did not describe it as particulate. Why is everyone assuming it is so?

Surely what is being described is simply an edge artefact which is seen *very* commonly on the edges of liver biopsies stained with Perl's. It is a faint blush - no more, and the clue to its being an artefact is that it is non-particulate and at the edge. PAS sometimes shows a similar phenomenon.

Beam me up Scottie.

Dr Terry L Marshall, B.A.(Law), M.B.,Ch.B.,F.R.C.Path
 Consultant Pathologist
 Rotherham General Hospital
 South Yorkshire

-----Original Message-----
From: Gayle Callis []
Sent: 18 November 2005 16:49
To: Rogerson Kemlo (ELHT) Pathology;
Subject: RE: [Histonet] formalin precipitate/Iron artifact

You are not talking rubbish.   We occasionally "pin" tissues to cork for 
fixation but use (aluminum?) hypodermic,disposable needles - they don't 
rust.   However, you bring up an excellent point as some pins, particularly 
those we thought useful and purchased from a sewing store did rust - tossed 
those out!!

A possible source of iron contamination is the specimen container with the 
lid as the culprit.  Years ago, before the advent of good specimen 
containers, people recycled baby food jars whose lids rusted excessively 
and exfoliated rust/iron contamination onto the samples during 
fixation.  If one has metal lids on containers, check them for rust and 
don't use them.

Or possibly, are they returning any reagent in some type of metal can?  We 
had metal cans whose liners failed, and rusted.   We used these for 
refilling/bulk alcohol storage and rusty gunk poured out!  Check the 
storage containers also.

At 05:56 AM 11/18/2005, you wrote:
>Could it be from the needle? Are needles made of iron? Am I talking

Gayle Callis
Research Histopathology Supervisor
Veterinary Molecular Biology
Montana State University - Bozeman
PO Box 173610
Bozeman MT 59717-3610
406 994-6367
406 994-4303 (FAX)

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